[xg15]

If someone actually links to moz://a, some crawlers might pick it up. But as a crawler has to parse the url and extract the scheme before it can continue, I don't see potential for confusion. Likely, "moz" wouldn't be in the list of supported schemes and the link would simply be dropped.

[wccrawford]

I think it likely that there will be regexes out there that auto-link it for people.